Reactions of iridium and ruthenium complexes with organic azides

Article abstract of DOI:10.1039/a703028b

Interaction of N₃R with Ir(mes)₃ (mes = mesityl, C₆H₂Me₃-2,4,6) gave products dependent on the nature of the azide. When R = mes, the tetrazenido amide complex 1 is obtained in which dehydrogenative coupling of the mesityl groups via the o-methyls has occurred; thermolysis of 1 in toluene resulted in cleavage of the tetrazene ring and formation of amide complex 2. When R = Ph, the aryl tetrazenido amide complex 3 is formed. Photolysis of a mixture of N₃(mes) and [RuCl₂(PPh₃)₃] followed by phosphine exchange gave the tetrazene complex [Ru^IICl₂{N₄(mes)₂} (PMe₃)₂] 4. Thermal reaction of [RuCl₂H₂(PPrⁱ₃)₂] with N₃(mes) gave the triazenophosphorane complex [RuCl₃(PPrⁱ₃) {N₃(mes)PPrⁱ₃}] 5. The ruthenium allyl amide [Ru(PMe₃)₃{NHC₆H₃Pr ⁱ(η³-CH₂CCH₂)}] 6 bearing a new hybrid ligand was obtained by interaction of trans[RuCl₂(PMe₃)₄] with Li[NH(C₆H₃Prⁱ₂-2,6)] in di-n-butyl ether. Plausible reaction mechanisms accounting for the formation of the new compounds are proposed. Finally, the crystal structures of the complexes 1-6 have been determined. Complexes 1 and 2 have pseudo-square planar geometries involving the olefin formed by the coupled methyl groups of two mesityls and three (1) or two (2) amide nitrogens and a chlorine atom (2). Compound 3 has a trigonal bipyramidal metal centre with the axial Ir-N amide bonds longer than the equatorial ones; 4 has an octahedral structure with a bidentate tetragonal ligand and trans phosphines whilst 5 is distorted octahedral with a N,N-chelating phosphazide ligand. Complex 6 is also octahedral with the allyl groups occupying cis sites and the three Ru-P bonds in a facial arrangement.

Full text of DOI:10.1039/a703028b

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Reactions of iridium and ruthenium complexes with organic azides†
Andreas A. Danopoulos,*,‡,a Robyn S. Hay-Motherwell,b (the late) Geoffrey Wilkinson,
Sean M. Cafferkey,c Tracy K. N. Sweet c and Michael B. Hursthouse*,c
a
Johnson Matthey Laboratory, Chemistry Department, Imperial College, London, UK SW7 2AY
b Christopher Ingold Laboratories, Department of Chemistry, University College London, 20
Gordon Street, London, UK WC1H 0AJ
c Department of Chemistry, University of Wales Cardiff, PO Box 912, Cardiff, UK CF1 3TB
Interaction of N3R with Ir(mes)3 (mes = mesityl, C6H2Me3-2,4,6) gave products dependent on the nature of
the azide. When R = mes, the tetrazenido amide complex 1 is obtained in which dehydrogenative coupling of
the mesityl groups via the o-methyls has occurred; thermolysis of 1 in toluene resulted in cleavage of the
tetrazene ring and formation of amide complex 2. When R = Ph, the aryl tetrazenido amide complex 3 is
formed. Photolysis of a mixture of N3(mes) and [RuCl2(PPh3)3] followed by phosphine exchange gave the
tetrazene complex [RuIICl2{N4(mes)2}(PMe3)2] 4. Thermal reaction of [RuCl2H2(PPri3)2] with N3(mes)
gave the triazenophosphorane complex [RuCl3(PPri3){N3(mes)PPri3}] 5. The ruthenium allyl amide
[Ru(PMe3)3{NHC6H3Pri(η3-CH2CCH2)}] 6 bearing a new hybrid ligand was obtained by interaction of trans-
[RuCl2(PMe3)4] with Li[NH(C6H3Pri2-2,6)] in di-n-butyl ether. Plausible reaction mechanisms accounting for the
formation of the new compounds are proposed. Finally, the crystal structures of the complexes 1–6 have been
determined. Complexes 1 and 2 have pseudo-square planar geometries involving the olefin formed by the coupled
methyl groups of two mesityls and three (1) or two (2) amide nitrogens and a chlorine atom (2). Compound 3 has
a trigonal bipyramidal metal centre with the axial Ir᎐N amide bonds longer than the equatorial ones; 4 has an
octahedral structure with a bidentate tetragonal ligand and trans phosphines whilst 5 is distorted octahedral with
a N,N-chelating phosphazide ligand. Complex 6 is also octahedral with the allyl groups occupying cis sites and the
three Ru᎐P bonds in a facial arrangement.
Interest in the chemistry of the late transition-metal imido
complexes stems from the belief that they may exhibit unusual
mes
reactivity towards a variety of substrates such as olefins, acety-
N
lenes and other small organic molecules.1 Despite recent signifi-
cant contributions in this area by several groups2–4 the chem-
istry of iridium and ruthenium imido compounds is still
underdeveloped.
mes
HC
HC
Ir
N
N
N
N
In an effort to explore new methods for the synthesis of such
species, we studied some reactions of aryl azides with readily
oxidisable ruthenium and iridium compounds in the hope that
this might constitute a simple route to imido complexes.
Although imido complexes were not isolated, the products
identified offer evidence for the involvement of metal–imido
intermediates.
We also describe the preparation of a ruthenium complex
bearing a new hybrid bidentate allyl amide ligand leading to the
stabilisation of uncommon ruthenium–amide bonds.
I
would not exhibit unfavourable steric interactions. Other
examples of IrV complexes are known or have been implicated
in various reactions.7
Interaction of an excess of N3(mes) with Ir(mes)3 gave, after
work-up an air stable blue paste as a dichloromethane solvate
of 1, which after crystallisation from ether gave blue crystals of
1. Attempts to establish the identity of the compound by NMR
spectroscopy were unsuccessful due to the complex and unin-
formative nature of the spectrum obtained. Therefore, an X-ray
diffraction study was undertaken. The structural formula for
the molecule is shown in structure I and a diagram from the
crystal structure determination in Fig. 1; important bond
lengths and angles are in Table 1.
The structure of compound 1 comprises an Ir metal centre
in a pseudo-square planar environment, co-ordinated to the
unusual tetradentate ligand by three amido N atoms and one
olefin, the latter being assumed to occupy one site. The olefin is
formally produced by dehydrogenative coupling and has a trans
configuration. The bond lengths and angles within the ligand
skeleton are consistent with the formulation shown in structure
I. The Ir᎐N bond trans to the olefin site, Ir᎐N(1) is slightly
longer than the other two, mutually trans Ir᎐N bonds [Ir᎐N(4),
Ir᎐N(5)]. This may be due to a trans influence from the olefin
bonding. The Ir᎐N3o plane, where o is the midpoint of the
olefin bond, is planar to within 0.08 Å. The C(23)᎐C(33) bond
Results and Discussion
Iridium and ruthenium tetrazene complexes
In order to investigate the accessibility of iridium imido com-
plexes via oxidative routes using organic azides as imido group
sources, we selected as starting material the 12eϪ three-co-
ordinate Ir(mes)3 (mes = C6H2Me3-2,4,6),5 because it is easily
and cleanly oxidised by oxygen or other oxo transfer reagents,
such as Me NO, to (mes) IrV᎐O.6 In addition, since compounds
᎐
3
3
5
of type Ir(mes)4 are known, a hypothetical (mes)N᎐Ir(mes)
᎐
3
† The work described herein was started, and several of the new com-
pounds identified, before Sir Geoffrey’s death last September. His co-
authors dedicate this paper with deep respect and great affection to the
lasting memory of a wonderful teacher, colleague and friend.
‡ Present address: Inorganic Chemistry Laboratory, University of
Oxford, South Parks Road, Oxford, UK OX1 3QR.
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184
3177

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Fig. 2 The structure of compound 2
Fig. 1 The structure of compound 1
mes
N
HC
HC
Ir Cl
Table 1 Bond lengths (Å) and angles (Њ) for compound 1
N
H
Ir᎐N(1)
Ir᎐N(4)
Ir᎐N(5)
N(1)᎐N(2)
N(2)᎐N(3)
N(3)᎐N(4)
C(23)᎐C(33)
2.013(9)
1.903(9)
1.918(10)
1.348(13)
1.288(13)
1.370(13)
1.41(2)
Ir᎐C(23)
Ir᎐C(33)
N(1)᎐C(11)
N(4)᎐C(21)
N(5)᎐C(31)
N(5)᎐C(41)
2.091(10)
2.128(11)
1.423(14)
1.460(14)
1.418(14)
1.452(13)
II
Table 2 Bond lengths (Å) and angles (Њ) for compound 2
N(4)᎐Ir᎐N(1)
N(4)᎐Ir᎐N(5)
N(5)᎐Ir᎐N(1)
N(1)᎐Ir᎐C(23)
N(1)᎐Ir᎐C(33)
N(4)᎐Ir᎐C(23)
N(4)᎐Ir᎐C(33)
N(5)᎐Ir᎐C(23)
N(5)᎐Ir᎐C(33)
C(23)᎐Ir᎐C(33)
C(31)᎐N(5)᎐C(41)
75.2(4)
173.7(4)
107.2(4)
152.9(4)
159.3(4)
82.0(4)
99.2(4)
94.1(4)
80.5(4)
39.1(4)
117.0(9)
N(2)᎐N(3)᎐N(4)
N(3)᎐N(2)᎐N(1)
N(2)᎐N(1)᎐Ir
110.5(10)
117.4(9)
114.9(7)
121.8(7)
113.7(9)
116.7(9)
131.0(8)
120.3(7)
120.3(7)
122.5(7)
Ir᎐N(1)
Ir᎐N(2)
Ir᎐Cl
N(2)᎐C(31)
C(23)᎐C(33)
1.939(6)
1.914(6)
2.343(2)
1.375(8)
1.426(9)
Ir᎐C(23)
Ir᎐C(33)
N(1)᎐C(11)
N(1)᎐C(21)
2.091(7)
2.097(6)
1.444(7)
1.426(8)
N(3)᎐N(4)᎐Ir
N(2)᎐N(1)᎐C(11)
N(3)᎐N(4)᎐C(21)
C(11)᎐N(1)᎐Ir
C(21)᎐N(4)᎐Ir
C(31)᎐N(5)᎐Ir
C(41)᎐N(5)᎐Ir
N(1)᎐Ir᎐C(23)
N(1)᎐Ir᎐C(33)
N(1)᎐Ir᎐Cl
N(2)᎐Ir᎐Cl
C(23)᎐Ir᎐Cl
80.7(3)
97.9(2)
94.9(2)
86.4(2)
157.5(2)
161.2(2)
117.5(6)
N(2)᎐Ir᎐C(23)
N(2)᎐Ir᎐C(33)
N(2)᎐Ir᎐N(1)
C(33)᎐Ir᎐C(23)
C(11)᎐N(1)᎐Ir
C(21)᎐N(1)᎐Ir
C(31)᎐N(2)᎐Ir
98.7(3)
80.5(2)
178.0(2)
39.8(2)
124.2(4)
117.7(4)
121.2(5)
C(33)᎐Ir᎐Cl
C(21)᎐N(1)᎐C(11)
makes an angle of 23.0Њ with this plane. The N᎐N distances in
the tetrazenyl ligand, with the centre bond shorter than the two
side bonds, are consistent with the formulation of the ligand as
shown in structure I. The IrN4 ring is planar to within 0.034 Å.
Compound 1 is thus a rare example of an amido complex of
iridium(). Its stability could be ascribed to the hybrid nature
of the ligand, which in addition to the π donating amido groups
has a π accepting olefinic site. The stability of another well
characterised amido complex of iridium()8 is also explained
on a similar basis, i.e. the use of amido–phosphine hybrid lig-
ands. Examples of IrI amides have been recently reported.9
The 1H NMR spectrum of 1 reflects the lack of any symmetry
elements in the molecule. All methyls attached to the aromatic
rings are magnetically inequivalent. The complete assignment
of the spectrum proved difficult. Although the mechanism of
formation of 1 is self evidently complex a plausible sequence is
discussed below in connection with compound 3.
It is worthwhile mentioning that decomposition products of
nitrene intermediates10 are not observed in this reaction, indicat-
ing that free nitrenes are not involved in productive steps. Bulk-
ier aryl azides, e.g. 2, 6-Pri2C6H3N3, or aryl azides with strongly
electron withdrawing groups (N3C6F5) known to be precursors
of stable nitrenes11 gave intractable mixtures after reaction with
Ir(mes)3. The reaction with N3Ph is discussed below.
Heating the previously mentioned solvate at 140 ЊC gives rise
to compound 2, shown in structure II and isolated in low to
moderate yield after chromatographic work-up and crystallis-
ation. A diagram of the molecule as determined by an X-ray
diffraction study is given in Fig. 2; important bond lengths and
angles are in Table 2. Its structure is related to that of 1, with
the common features in the diamidoalkene ligand showing very
similar metric parameters. The IrN2Clo group is planar to with-
in 0.06 Å and the olefin bond makes an angle of 27.4Њ with this
plane. The formal oxidation state for the Ir centre is also .
In this unusual chemical transformation, which formally
requires the loss of N3(mes) from 1, the only possible source of
the chlorine atom is CH2Cl2. Homolytic pathways with possible
electron transfer could be operating.
In order to gain more insight into the mechanism of forma-
tion of 1, and in particular to trace the origin of each mesityl
group in the final product, we studied the interaction of
Ir(mes)3 with N3Ph. In this instance, due to the absence of the
flanking o-methyl groups in the azide, the reaction followed a
different pathway as witnessed by the product 3 isolated. Com-
pound 3 was characterised by accurate mass spectroscopy (see
Experimental section) and X-ray crystallography. Reliable ana-
lytical data could not be obtained possibly due to facile loss of
dinitrogen or incomplete combustion even when a combustion
catalyst was used. The structure of 3, which is formally an IrV
complex was determined by X-ray diffraction and is shown
Compound 1 shows good thermal stability in the solid state
indicating the reluctance of the tetrazene ring to undergo N2
extrusion.Similarobservationswerepreviouslymadeforcobalt,12
rhodium, iridium 4a and ruthenium 4a tetrazene complexes.
3178
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184

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mes
mes
mes
(i)
(ii)
(mes)3IrV Nmes
Ir(mes)3
IrIII
N
mes
(iii)
mes
mes
N
mes
mes
mes
mes
(iv)
Ir
N
IrV
mes
N
Nmes
N
mes
mes
mes
N
N
(v)
mes
N
mes
H2C H
H2C H
N
mes
H2C
H2C
vi)
Ir
N
(
Ir
N
N
N
N
N
Fig. 3 The structure of compound 3
mes
N
N
(vii)
mes
Ph
mes
N
N
mes
N
N
Ir
N
N
mes
N
N
HC
HC
Ir
Ph
Ph
N
N
III
N
Table 3 Bond lengths (Å) and angles (Њ) for compound 3
Scheme 1 Proposed mechanism for the formation of compound 1: (i)
N3(mes), -N2; (ii) rearrangement; (iii) oxidative addition; (iv) N3(mes),
cycloaddition; (v) intramolecular rearrangement; (vi) -2Hmes; (vii) -H2
Ir᎐N(1)
1.975(5)
2.034(6)
1.928(6)
2.011(6)
2.110(6)
1.352(8)
1.445(8)
N(3)᎐N(4)
N(4)᎐N(5)
N(5)᎐N(6)
N(1)᎐C(1)
N(1)᎐C(7)
N(2)᎐C(16)
N(6)᎐C(28)
1.384(7)
1.314(8)
1.327(7)
1.372(8)
1.443(8)
1.428(9)
1.431(8)
Ir᎐N(2)
Ir᎐N(3)
mes
IrIII
mes
Ph
(i)
(ii)
Ir᎐N(6)
(mes)3IrV NPh
Ir(mes)3
N
Ir᎐C(42)
N(2)᎐C(6)
N(3)᎐C(22)
mes
mes
mes
N
IrIII
N
mes
mes
N(1)᎐Ir᎐N(2)
N(1)᎐Ir᎐N(6)
N(3)᎐Ir᎐N(1)
N(3)᎐Ir᎐N(2)
N(3)᎐Ir᎐N(6)
N(6)᎐Ir᎐N(2)
N(4)᎐N(3)᎐Ir
N(5)᎐N(6)᎐Ir
C(1)᎐N(1)᎐C(7)
C(6)᎐N(2)᎐C(16)
79.0(2)
99.4(2)
135.7(2)
99.2(2)
N(1)᎐Ir᎐C(42)
N(2)᎐Ir᎐C(42)
N(3)᎐Ir᎐C(42)
N(6)᎐Ir᎐C(42)
N(4)᎐N(5)᎐N(6)
N(5)᎐N(4)᎐N(3)
C(1)᎐N(1)᎐Ir
C(6)᎐N(2)᎐Ir
C(7)᎐N(1)᎐Ir
C(16)᎐N(2)᎐Ir
108.7(2)
95.1(2)
115.5(2)
93.8(2)
115.3(5)
112.6(5)
116.6(5)
115.0(5)
112.0(4)
125.5(4)
mes
mes
(iii)
Irv
H
H
N
Ph
(iv)
75.6(2)
171.0(2)
118.9(4)
117.0(4)
117.8(5)
119.4(6)
mes
mes
N
N
mes
H
mes
mes
(v)
Irv
IrIII
N
mes
N
H
Ph
(vi)
Ph
schematically in structure III. A crystal structure diagram of
the molecule is shown in Fig. 3; important bond lengths and
angles are given in Table 3. The metal co-ordination is now
slightly distorted trigonal bipyramidal, with the two chelating
ligands each spanning one axial and one equatorial site. The
IrN4 ring has a shallow envelope configuration with the four N
atoms planar to within 0.024 Å, and the Ir atom 0.15 Å out of
the plane. The C2N2Ir ring is considerably buckled, with devi-
ations of up to 0.5 Å. The axial Ir᎐N bonds [Ir᎐N(2), Ir᎐N(6)]
are much lengthened and are longer than the equatorial one
[Ir᎐N(3)], demonstrating the different π bonding capabilities of
the axial and equatorial sites in IrIII and IrV complexes. The
Ir᎐C distance is very similar to that in compounds 1 and 2. The
tetraazenyl geometry is again consistent with the formulation
shown, making it a formal 2 (Ϫ) ligand.
mes
N
IrIII
mes
N
Ir
(vii)
NPh
mes
mes
N
N
Ph
(viii)
Ph
Ph
mes
mes
N
N
Irv
N
N
N
N
Ph
Ph
Scheme 2 Proposed mechanism for the formation of compound 3: (i)
N3Ph, -N2; (ii) rearrangement; (iii) N3Ph, -N2; (iv) rearrangement;
(v) transfer of o-H; (vi) -Hmes; (vii) N3Ph, -N2; (viii) N3Ph, -N2
Plausible mechanisms for the formation of 1 and 3 are shown
in Schemes 1 and 2, respectively. Initial interaction of an aryl
azide with Ir(mes)3 could lead to the formation of a transient
arylimido trimesityl iridium which could rearrange to a mesityl
imido iridium() complex [steps (i) and (ii)]. Alternatively,
insertion of an aryl azide into the Ir᎐C bond leads directly to
the intermediate (mes)2IrNR(mes) (R = aryl) for an analogous
nickel reaction, see ref. 13. After this step the proposed reaction
pathways diverge, the nature of the product depending on
the presence or absence of the crucial o-methyl groups in the
aromatic ring (R) of the reacting azide.
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184
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PPri3
Ru
Cl
Cl
Cl
R
N
N
N
PPri3
V
Irradiation of a mixture of [RuCl2(PPh3)3] and N3(mes) in
tetrahydrofuran (thf)–methanol in a quartz vessel followed by
exchange of PPh3 with PMe3 in situ gave not the anticipated
imido but the tetrazene complex cis,trans-dichloro(1,4-
dimesityltetraza-1,3-diene)bis(trimethylphosphine)ruthenium-
() 4 (structure IV). It is diamagnetic and its identity is easily
established by analytical and NMR spectroscopic (1H and 31P)
data. Its structure has been determined by diffraction methods
and is shown in Fig. 4; important bond lengths and angles are
in Table 4. The metal geometry is close to octahedral, with the
phosphines trans to the co-ordinating nitrogens of the bidentate
tetrazene ligand. The pseudo C 2v symmetry of the RuCl2N2P2
molecular core is reflected in the close similarities in the pairs of
Ru᎐Cl, Ru᎐P and Ru᎐N bonds and in the N(1)᎐N(2),
N(3)᎐N(4) bonds. It is pertinent to note that these two bonds
are slightly shorter than the central N(2)᎐N(3) bond, consistent
with the formation of the ligand as a 2 × 2eϪ donor, and the
metal as RuII as shown in structure IV. The RuN4 ring is planar
to within 0.09 Å.
Fig. 4 The structure of compound 4
Cl
Me3P
Ru
Cl
N
PMe3
R
R
N
N
N
IV
Table 4 Bond lengths (Å) and angles (Њ) for compound 4
Ru᎐N(1)
Ru᎐N(4)
Ru᎐Cl(1)
Ru᎐Cl(2)
Ru᎐P(1)
2.022(3)
2.033(3)
P(1)᎐C(1)
P(1)᎐C(2)
P(1)᎐C(3)
P(2)᎐C(4)
P(2)᎐C(5)
P(2)᎐C(6)
N(1)᎐C(10)
N(4)᎐C(20)
1.817(5)
1.806(5)
1.799(4)
1.807(5)
1.809(5)
1.837(5)
1.448(5)
1.454(5)
2.3636(11)
2.3655(12)
2.4194(12)
2.3988(13)
1.307(4)
Ru᎐P(2)
N(1)᎐N(2)
N(2)᎐N(3)
N(3)᎐N(4)
The only other products identified in the reaction mixture by
31P NMR spectroscopy are (mes)N᎐PPh and [RuCl (PMe ) ],
1.338(4)
1.313(4)
᎐
3
2
3 4
the latter resulting from the interaction of unreacted
[RuCl2(PPh3)3] with PMe3. Compound 4 is thermally stable in
the solid state and in solution. It does not react with donors like
PMe3 or pyridine even under forcing conditions (refluxing tolu-
ene or UV irradiation). Its formation could have resulted from
the insertion of excess azide to a transient ruthenium imido
intermediate. Ruthenium() imido complexes are known to
participate in insertion reactions giving tetrazene complexes.4a
Attempts to isolate this intermediate by using a deficiency of
the azide resulted only in a reduced yield of 4.
N(1)᎐Ru᎐N(4)
P(2)᎐Ru᎐P(1)
73.22(13)
91.10(4)
97.71(9)
93.68(9)
93.38(9)
98.25(9)
89.07(4)
80.75(4)
80.67(4)
89.39(4)
103.2(3)
98.1(2)
101.7(2)
103.4(3)
96.9(2)
101.3(2)
107.4(3)
Cl(1)᎐Ru᎐Cl(2)
N(1)᎐Ru᎐P(1)
N(1)᎐Ru᎐P(2)
N(4)᎐Ru᎐P(1)
N(4)᎐Ru᎐P(2)
C(1)᎐P(1)᎐Ru
C(2)᎐P(1)᎐Ru
C(3)᎐P(1)᎐Ru
C(4)᎐P(2)᎐Ru
C(5)᎐P(2)᎐Ru
C(6)᎐P(2)᎐Ru
N(2)᎐N(1)᎐Ru
N(3)᎐N(4)᎐Ru
N(1)᎐N(2)᎐N(3)
N(4)᎐N(3)᎐N(2)
N(2)᎐N(1)᎐C(10)
165.65(4)
98.20(9)
170.57(10)
171.31(10)
97.52(10)
115.6(2)
118.2(2)
117.1(2)
118.1(2)
116.9(2)
117.0(2)
119.4(2)
118.6(2)
114.2(3)
114.4(3)
107.7(3)
N(1)᎐Ru᎐Cl(1)
N(1)᎐Ru᎐Cl(2)
N(4)᎐Ru᎐Cl(1)
N(4)᎐Ru᎐Cl(2)
Cl(1)᎐Ru᎐P(1)
Cl(1)᎐Ru᎐P(2)
Cl(2)᎐Ru᎐P(1)
Cl(2)᎐Ru᎐P(2)
C(2)᎐P(1)᎐C(1)
C(3)᎐P(1)᎐C(1)
C(3)᎐P(1)᎐C(2)
C(4)᎐P(2)᎐C(5)
C(4)᎐P(2)᎐C(6)
C(5)᎐P(2)᎐C(6)
N(3)᎐N(4)᎐C(20)
A ruthenium triazenophosphorane complex
Interaction of N3(mes) with the recently reported ruthenium()
complex [RuH2Cl2(PPri3)2] gave rise to a paramagnetic triazeno-
phosphorane complex of RuIII mer-trichloro(triisopropyl-
phosphine){3-(triisopropylphosphoranediyl)-1-mesityltriaz-1-
ene}ruthenium() 5, shown schematically in structure V, which
was fully characterised by analytical data and a X-ray diffrac-
tion study.
The ligand RNNNPRЈ3 (R = aryl, RЈ = alkyl or aryl) origin-
ally named by Staudinger as phosphazide is an intermediate
in reactions between organic azides and phosphines. It is
usually unstable at room temperature unless the azide carries
electron-withdrawing substituents. A discussion of these inter-
mediates together with recent advances in the Staudinger reac-
tion has appeared.15 Triazenophosphorane is related to the
diazenylimido ligand (e.g. end-on co-ordinated organic azide)
recently reported by Proulx and Bergman 16 and Cummings
and co-workers.17
When R = mes, a second oxidative addition followed by
cycloaddition of a further molecule of the azide to the resulting
arylimido complex leads to an IrV intermediate [steps (iii) and
(iv)], which after elimination of two molecules of mesitylene
followed by dehydrogenation [steps (v)–(vii)] gives the final
product. It is pertinent to note at this point that bimesityl was
not detected in the reaction mixture by spectroscopic methods.
When R = Ph, a second oxidative addition of the NPh group
is followed by transfer of the o-hydrogen to the metal centre
[steps (iii)–(v)]. Finally, reductive elimination of mesitylene fol-
lowed by addition of another NPh group and a final azide
cycloaddition gives the observed product [steps (vi) and (vii)].
The observed reactivity difference can be ascribed both to the
steric congestion of the flanking o-methyl groups, their
reluctance to undergo migration and the inertness of aliphatic
C᎐H bonds.
To our knowledge the only other structurally characterised
example of a triazenophosphorane complex is [W(CO)2Br-
(tolNNNPPh3)] (tol = p-tolyl, C6H4Me-4) reported by Hill-
house et al.18
Based on the isoelectronic relationship between carbenes
and nitrenes and the recently reported 14 preparation of ruth-
enium() carbene complexes by interaction of [RuCl2(PPh3)3]
with N2CHPh, the latter acting as a carbene precursor, we
applied similar methodology using N3(mes), which when
irradiated in polar solvents can act as a nitrene precursor.
The crystal structure of complex 5 is shown in Fig. 5;
important bond lengths and angles are in Table 5. The molecule
has a distorted octahedral geometry which is mer with respect
to the three chlorine atoms. The Ru᎐N bonds, which are trans to
P and Cl are remarkably similar in length, as are the three
Ru᎐Cl bonds. In the tungsten complex mentioned above,18 the
3180
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184

View Article Online
Fig. 6 The structure of the ruthenium amide 6
PMe3
Me3P
PMe3
NH
Ru
H2C
C
CH2
Fig. 5 The structure of compound 5
Pri
Table 5 Bond lengths (Å) and angles (Њ) for compound 5
VI
Ru᎐N(1)
Ru᎐N(2)
Ru᎐N(3)
Ru᎐P(1)
N(1)᎐N(3)
P(1)᎐C(20)
P(1)᎐C(30)
P(1)᎐C(40)
2.151(4)
2.150(5)
2.671(5)
2.367(2)
1.361(6)
1.839(7)
1.858(7)
1.854(6)
Ru᎐Cl(1)
Ru᎐Cl(2)
Ru᎐Cl(3)
N(1)᎐P(2)
N(2)᎐N(3)
P(2)᎐C(50)
P(2)᎐C(60)
P(2)᎐C(70)
2.349(2)
2.348(2)
2.341(2)
1.672(5)
1.286(6)
1.813(6)
1.814(6)
1.797(5)
Table 6 Bond lengths (Å) and angles (Њ) for compound 6
Ru(1)᎐N(1)
Ru(1)᎐P(1)
Ru(1)᎐P(2)
Ru(1)᎐P(3)
Ru(1)᎐C(10)
Ru(1)᎐C(11)
Ru(1)᎐C(12)
N(1)᎐C(1)
2.138(3)
Ru(2)᎐N(2)
Ru(2)᎐P(4)
Ru(2)᎐P(5)
Ru(2)᎐P(6)
Ru(2)᎐C(31)
Ru(2)᎐C(32)
Ru(2)᎐C(33)
N(2)᎐C(22)
2.137(3)
2.3206(11)
2.3146(12)
2.3133(13)
2.198(3)
2.281(4)
2.258(4)
2.2934(12)
2.3035(12)
2.3112(11)
2.197(3)
2.302(4)
2.242(4)
N(1)᎐Ru᎐N(2)
N(1)᎐Ru᎐Cl(1)
N(1)᎐Ru᎐Cl(2)
N(1)᎐Ru᎐Cl(3)
N(2)᎐Ru᎐Cl(1)
N(2)᎐Ru᎐Cl(2)
N(2)᎐Ru᎐Cl(3)
Cl(1)᎐Ru᎐P(1)
Cl(2)᎐Ru᎐P(1)
Cl(3)᎐Ru᎐P(1)
N(3)᎐N(1)᎐Ru
N(3)᎐N(2)᎐Ru
58.8(2)
89.35(12)
90.00(12)
98.77(14)
88.89(13)
87.98(13)
157.50(13)
91.39(6)
88.88(6)
87.93(6)
96.4(3)
N(1)᎐Ru᎐P(1)
N(2)᎐Ru᎐P(1)
N(1)᎐Ru᎐N(3)
N(2)᎐Ru᎐N(3)
Cl(1)᎐Ru᎐Cl(2)
Cl(3)᎐Ru᎐Cl(1)
Cl(3)᎐Ru᎐Cl(2)
Cl(1)᎐Ru᎐N(3)
Cl(2)᎐Ru᎐N(3)
Cl(3)᎐Ru᎐N(3)
N(3)᎐N(1)᎐P(2)
N(2)᎐N(3)᎐N(1)
173.22(14)
114.47(14)
30.4(2)
1.350(4)
1.349(4)
28.4(2)
N(1)᎐Ru(1)᎐C(10)
N(1)᎐Ru(1)᎐C(11)
N(1)᎐Ru(1)᎐C(12)
N(1)᎐Ru(1)᎐P(1)
N(1)᎐Ru(1)᎐P(2)
N(1)᎐Ru(1)᎐P(3)
P(2)᎐Ru(1)᎐P(1)
P(3)᎐Ru(1)᎐P(1)
P(3)᎐Ru(1)᎐P(2)
C(10)᎐Ru(1)᎐C(11)
C(10)᎐Ru(1)᎐C(12)
C(12)᎐Ru(1)᎐C(11)
75.26(12)
91.35(13)
93.07(13)
82.08(9)
178.19(9)
86.81(9)
98.62(4)
101.73(5)
91.42(5)
N(2)᎐Ru(2)᎐C(31)
N(2)᎐Ru(2)᎐C(32)
N(2)᎐Ru(2)᎐C(33)
N(2)᎐Ru(2)᎐P(4)
N(2)᎐Ru(2)᎐P(5)
N(2)᎐Ru(2)᎐P(6)
P(4)᎐Ru(2)᎐P(5)
P(4)᎐Ru(2)᎐P(6)
P(5)᎐Ru(2)᎐P(6)
C(31)᎐Ru(2)᎐C(32)
C(31)᎐Ru(2)᎐C(33)
C(33)᎐Ru(2)᎐C(32)
74.79(11)
93.28(13)
90.63(14)
88.57(9)
175.16(9)
84.03(9)
95.39(5)
100.22(4)
92.50(5)
35.79(13)
37.64(13)
65.5(2)
176.68(7)
92.90(6)
90.41(6)
89.33(11)
88.45(11)
129.15(12)
115.2(4)
105.8(4)
99.0(4)
36.88(13)
36.57(13)
65.73(14)
W᎐N distances are different, probably reflecting the occupancy
of a normal and a capping site in a capped octahedral co-
ordination geometry. Bond lengths in the triazenophosphorane
of 5 are consistent with its formulation as RN᎐N᎐N᎐PR . The
Ru atom is 0.039 Å out of the N3 plane.
The reduction of ruthenium during the present transform-
ation combined with the fact that less than 50% yields are
obtained is indicative of a disproportionation reaction as a
productive step. No other products have been isolated.
2
᎐
᎐
3
Furthermore, the magnitude of JP᎐P (31 Hz) indicates cis
arrangement of the coupled nuclei. In the H NMR spectrum
1
the presence of the allyl group is evidenced by the appearance
of an A2B2 pattern which can be assigned to the magnetically
inequivalent exo and endo protons of the η3-CH2(CRЈ)CH2
(RЈ = NHC6H3Pri) group. Complex 6 is non-fluxional in
[2H8]toluene between Ϫ50 and ϩ80 ЊC.
A ruthenium amide complex
The structure of 6, shown schematically in structure VI has
been determined by X-ray diffraction methods. The structure
contains two crystallographically independent molecules which
are essentially equivalent. A diagram of one molecule is shown
in Fig. 6; important bond lengths and angles are given in Table 6.
The metal geometry is distorted octahedral, with the allyl func-
tions assumed to occupy two cis sites and the phosphines have a
fac arrangement. Notwithstanding the site differences, i.e. trans
to N or allyl carbons, the Ru᎐P distances are all very similar.
A plausible mechanism accounting for the formation of 6
is shown in Scheme 3 and involves substitution of the first
The compound trans-[RuCl2(PMe3)4] is relatively inert in substi-
tution reactions of chloride by anionic amides.19,20 However,
interaction with 2 equivalents of Li[NH(C6H3Pri2-2,6)] in
refluxing dibutyl ether gave after work-up crystalline allyl–
amide (2-isopropyl-6-yloallylphenylamido)tris(trimethylphos-
phine)ruthenium() 6, which contains a novel dianionic hybrid
ligand. Complex 6 was adequately characterised by spectro-
scopic (NMR) and analytical methods. The 31P NMR spectrum
consists of an A2B pattern supporting the presence of two
groups of magnetically inequivalent phosphorus nuclei.
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184
3181

View Article Online
Table 7 Analytical and physical data for new compounds
Analysis (%)a
C
Compound
Colour
M.p./ЊC
H
N
1
3
4
5
6
Blue
143–145 (decomp.)
171–173
222–225
205 (decomp.)
165 (decomp.)
59.1 (58.9)
b
42.3 (42.7)
46.5 (47.0)
49.8 (50.0)
5.8 (5.5)
9.2 (9.5)
Blue-grey
Orange-red
Orange
Yellow
5.7 (5.9)
7.7 (7.7)
8.3 (8.5)
8.1 (8.3)
5.9 (6.1)
2.5 (2.8)
a
Calculated values in parentheses. b No reliable analytical data available, for accurate mass spectra see below.
[RuCl2(PMe3)4] + Li[NH(C6H3Pri2)-2,6]
[RuCl{NH(C6H3Pri2)}]
Aldrich and Avocado. The light petroleum used had b.p.
40–60 ЊC.
The following starting materials were prepared as referenced:
N3(mes),22 N3Ph,23 Ir(mes)3,5 [RuCl2(PPh3)3],24 trans-[RuCl2-
(PMe3)4],25 [RuH2Cl2(PPri3)2];26 the compound Li[NH(C6H3Pri2-
2,6)] was prepared by interaction of distilled aniline with
the stoichiometric amount of LiBun in light petroleum.
Photolysis were carried out in a quartz apparatus using a 125
W medium pressure Hg lamp.
(ii)
H
N
Ru
N
H
(iii)
Ru
B–
Cl
Path A
Path B
Analytical and physical data for the new compounds are
given in Table 7.
H
Compound 1
N
HN
Ru
H
Ru
To a stirred solution of Ir(mes)3 (0.14 g, 0.26 mmol) in diethyl
ether (15 cm3) was added a solution of N3(mes) (0.165 g, 1.02
mmol) in diethyl ether (15 cm3). After stirring the reaction mix-
ture at room temperature for 8 h, the volatiles were removed
under vacuum and the residue was extracted with light petrol-
eum (2 × 10 cm3). Removal of light petroleum under reduced
pressure gave the crude product, which was further purified
by column chromatography (neutral alumina, activity I, the
elution was started using hexane followed by hexane to which
CH2Cl2 was added in 6% steps up to 50% CH2Cl2). The dark
blue air-stable paste obtained by evaporation of volatiles under
reduced pressure which is a CH2Cl2 solvate of 1 (by NMR spec-
troscopy) was crystallised from diethyl ether, by slow evapor-
ation to give dark blue crystals of 1. Yield: 0.125 g, 67%. NMR
(C6D6): 1H, δ 7.05, 7.02, 6.72, 6.57, 6.50, 6.39, 6.37, 6.03 (s, 1 H
H
(iv)
(v)
N
HN
RuIV
H
Ru
H
H
H
(vi)
HN
RuII
HN
RuII
Scheme 3 Proposed mechanism for the formation of the ruthenium
amide 6: (i) -LiCl; (ii) -ClϪ, -B, -H; (iii) pericyclic H migration (path A)
or C᎐H bond addition (path B); (iv) β-hydride elimination; (v) oxida-
tive addition; (vi) -H2
each, aromatic), 5.56 (d, 1 H, CH᎐CH, J = 9.4), 4.90 (d, 1 H,
᎐
CH᎐CH, J = 9.4 Hz), 2.88, 2.21, 2.15, 2.08, 2.06, 2.05, 1.93,
᎐
1.90, 1.58 and 1.29 (s, 3 H each, CH3).
chloride by the amide group and base-induced dehydrohalogen-
ation [steps (i) and (ii)] to generate the ruthenium imido complex
as a key intermediate. Formal dehydrogenation of one of the
neighbouring ortho isopropyl groups can then occur either via a
series of two consecutive pericyclic hydrogen migrations (path
A) or via the cyclometallated intermediate formed by addition
of a C᎐H bond of the methyl group across the ruthenium imido
bond [step (iii), path B] and subsequent β-hydride elimination
[step (iv)]. Oxidative addition of one of the C᎐H bonds of the
activated allylic methyl group [step (v)] and a final dihydrogen
reductive elimination [step (vi)] can then account for the
observed product.
Compound 2
A solution of a crude CH2Cl2 solvate of 1 in toluene (0.03 g in
10 cm3) in a sealed tube was heated to 140 ЊC for 4 h. After
cooling to room temperature and removal of volatiles under
vacuum, the residue was purified by column chromatography
on neutral alumina (activity I). The elution was started with
hexane followed by hexane to which diethyl ether was added in
10% steps up to 50% diethyl ether. Evaporation of volatiles
from the combined eluents gave 2 as a dark grey-blue solid.
Yield: 0.005–0.01 g, 20–40%. X-Ray quality crystals were
obtained by slow evaporation of diethyl ether solutions. NMR
(CD2Cl2): 1H, δ 12.70 (s, 1 H, NH), 7.25, 7.20, 6.87, 6.62 (s, 1 H
each, aromatic), 6.81 (br s, 2 H aromatic), 5.88 (d, 1 H,
Experimental
CH᎐CH, J = 8.7), 5.68 (d, 1 H, CH᎐CH, J = 8.7 Hz), 2.34, 2.24,
᎐
᎐
Analyses were by Imperial College microanalytical laboratory.
All operations were carried out under purified Ar or N2, under
vacuum or in a Vacuum Atmospheres glove-box. General tech-
niques have been described previously.21 The NMR spectro-
scopic data were obtained on a JEOL EX-270, a Bruker Avance
DRX-300 or a Varian VRX-400 spectrometer operating at 270,
300 or 400 MHz (1H), respectively and referenced to the
residual 1H impurity in the solvent (δ 7.15, C6D6; 7.26, CDCl3,
5.3, CD2Cl2); 31P spectra were referenced externally relative to
H3PO4. Mass spectra were recorded using VG-7070E and VG
Autospec spectrometers. Commercial chemicals were from
2.15, 1.94, 1.84, 1.60 and 1.27 (s, 3 H each, CH3).
Compound 3
To a stirred solution of Ir(mes)3 (0.1 g, 0.18 mmol) in diethyl
ether (20 cm3) was added a solution of N3Ph in hexane (4.7 cm3
of 0.14 ). The reaction mixture was stirred vigorously at room
temperature for 2 d. After removal of the volatiles under vac-
uum the crude air stable product was purified by column chro-
matography on neutral alumina, activity I. The elution was
started using light petroleum, followed by light petroleum to
3182
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184

Table 8 Crystal data and structure refinement details for compounds 1–6
1
2
3
4
5
6
Formula
Mr
Crystal system
Space group
[C36H40IrN5][C2H5O]0.5 C27H29ClIrN2
C42H41IrN6
822.01
Monoclinic
C2/c
C24H40Cl2N4P2Ru
618.51
Trigonal
R3c
C30H53Cl3N3P2Ru
725.14
Monoclinic
P21/c
C42H84N2P6Ru2
1 005.07
Monoclinic
P21/n
750.94
609.17
Triclinic
P1
Monoclinic
P21/n
¯
a/Å
b/Å
c/Å
α/Њ
11.022(4)
11.871(3)
13.493(3)
74.76(5)
11.464(4)
12.1730(10)
16.887(3)
28.494(6)
19.187(4)
15.604(3)
27.222(4)
27.222(4)
20.426(4)
90
9.9780(10)
10.798(3)
33.685(2)
17.797(7)
11.726(2)
25.3200(10)
β/Њ
76.45(4)
90.627(11)
112.34(3)
90
94.79(2)
110.00(4)
γ/Њ
87.19(2)
1655.8(8)
2
1.506
752
120
13 109(4)
18
1.410
5760
U/Å3
2356.5(9)
4
1.717
1196
7891(3)
8
1.384
3296
3616.6(11)
4
4965(2)
4
Z
Dc/Mg mϪ3
1.332
1516
1.345
2112
F(000)
Crystal size/mm
µ(Mo-Kα)/mmϪ1
T/K
0.18 × 0.18 × 0.12
3.926
150
0.12 × 0.15 × 0.13 0.18 × 0.16 × 0.05 0.17 × 0.12 × 0.09 0.13 × 0.15 × 0.15 0.17 × 0.28 × 0.12
5.600
3.419
0.810
0.733
0.783
150
150
150
150
150
Reflections collected
Independent reflections (Rint
Maximum, minimum correction factors
Data, restraints, parameters
Goodness of fit, F 2
6486
8677
31 834
17 890
13 581
19 723
)
4624 (0.0804)
1.285, 0.811
4622, 18, 406
1.046
3454 (0.0577)
1.133, 0.866
3452, 0, 287
0.639
5836 (0.0607)
1.100, 0.998
5836, 0, 448
0.871
4092 (0.0654)
1.044, 0.919
4090, 1, 310
0.868
5235 (0.0943)
1.138, 0.700
5228, 0, 394
0.827
7234 (0.0607)
1.097, 0.914
7230, 0, 805
0.789
Final R1, wR2* [I > 2σ(I)]
(all data)
0.0582, 0.1429
0.0691, 0.1550
2.400, Ϫ1.601
0.0277, 0.0519
0.0523, 0.0547
1.156, Ϫ0.561
0.0332, 0.0690
0.0668, 0.0729
1.450, Ϫ0.679
0.0247, 0.0514
0.0313, 0.0627
0.293, Ϫ0.316
0.0462, 0.0843
0.0946, 0.1043
0.637, Ϫ0.350
0.0280, 0.0536
0.0435, 0.0712
0.470, Ϫ0.438
Largest difference peak and hole/e ÅϪ3
¹
¹
*Goodness of fit, S = [Σw(Fo2 Ϫ Fc )2/(n Ϫ p)]² where n = number of reflections and p = total number of parameters; R1 = Σ|Fo Ϫ Fc|/ΣFo; wR2 = [Σ(Fo2 Ϫ Fc )2/Σw(Fo2)2]² where w = 1/[σ2(Fo)2 ϩ (xP)2] with x = 0.0759,
2
2
0.0000, 0.0193, 0.0140, 0.0183 and 0.0000 for 1, 2, 3, 4, 5 and 6 and P = [max(Fo2) ϩ (2Fc )]/3.
2

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which diethyl ether was added in steps of 4% up to 16% diethyl
ether. The dark blue solid obtained after evaporation of volat-
iles from the combined eluents was further purified by slow
evaporation of light petroleum solutions. Yield: 0.0218 g, 14%.
Accurate chemical ionization (CI) mass spectrum: m/z 822.3052
(Calc. for C42H41IrN6 822.3022) and 794.2967 (Mϩ Ϫ N2).
NMR (C6D6): 1H, δ 7.60–6.51 (m, 21 H, aromatic), 6.47, 6.16 (s,
1 H each, C6H2Me3), 2.23, 2.11, 2.05, 1.67, 1.54, 0.78 (s, 3 H
each, C6H2Me3).
experimentally. In the crystal structure of 1 a disordered solvent
molecule (diethyl ether) appeared to be present at partial occu-
pancy in a cavity around 0.5, 0, 0. It was not possible to model
this to a chemically sensible structure but partial atoms were
included coincident with the three major peaks present in the
difference map. Refinement indicates an occupancy of about 0.5.
CCDC reference number 186/630.
Acknowledgements
We thank Professor W. B. Motherwell (University College
London) for helpful discussions and interest. A. A. D. and
S. M. C. are indebted to the Wilkinson Trust for financial
support. Partial support by EPSRC is also acknowledged (to
R. S. H.-M.).
Compound 4
To a solution of [RuCl2(PPh3)3] (0.48 g, 0.5 mmol) in thf–
methanol (20 cm3, 2:1) at room temperature was added a solu-
tion of N3(mes) in thf (0.17 g, 1.0 mmol in 10 cm3) and the
mixture was photolysed for 2 h. During this time N2 evolution
was observed. After addition of more N3(mes) (0.08 g, 0.5
mmol) photolysis was continued for 2 h. To the yellow-brown
reaction mixture obtained was added PMe3 (0.4 cm3, excess)
and stirring continued for 4 h. Evaporation of volatiles under
reduced pressure, extraction of the residue with light petroleum
until the extracts were colourless (ca. 4 × 20 cm3), followed by
concentration of the filtered extracts to ca. 20 cm3 and standing
at room temperature for 8 h gave orange-red prisms. Yield: 0.17
g, 55%. NMR (C6D6): 1H, δ 6.65 (s, 4 H, C6H2Me3), 2.32 (s, 12
H, o-Me2C6H2Me), 2.18 (s, 6 H, p-MeC6H2Me2) and 0.98
(filled-in d, 18 H, PMe3); 31P, δ Ϫ17.7 (s).
References
1 W. A. Nugent and J. M. Mayer, Metal-Ligand Multiple Bonds, Wiley,
New York, 1988; D. E. Wigley, Prog. Inorg. Chem., 1994, 42, 239.
2 D. S. Glueck, J. Wu, F. J. Hollander and R. G. Bergman, J. Am.
Chem. Soc., 1991, 113, 2041; D. A. Dobbs and R. G. Bergman,
Organometallics, 1994, 13, 4594.
3 A. K. Burrell and A. J. Steedman, J. Chem. Soc., Chem. Commun.,
1995, 2109.
4 (a) A. A. Danopoulos, G. Wilkinson, B. Hussain-Bates and M. B.
Hursthouse, J. Chem. Soc., Dalton Trans., 1996, 3771; (b) A. A.
Danopoulos, G. Wilkinson, B. Hussain-Bates and M. B. Hurst-
house, Polyhedron, 1992, 11, 2961.
5 R. S. Hay-Motherwell, G. Wilkinson, B. Hussain-Bates and M. B.
Hursthouse, J. Chem. Soc., Dalton Trans., 1992, 3477.
6 R. S. Hay-Motherwell, G. Wilkinson, B. Hussain-Bates and M. B.
Hursthouse, Polyhedron, 1993, 12, 2009.
7 F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry,
Wiley, NewYork, 5th edn., 1988, p. 916;X.-L. Luo and R. H. Crabtree,
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Organometallics, 1991, 10, 615.
8 M. D. Fryzuk, P. A. McNeil and S. Rettig, Organometallics, 1986, 5,
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9 M. Rahim and K. J. Ahmet, Organometallics, 1994, 13, 1751.
10 P. A. S. Smith, in Azides and Nitrenes, Reactivity and Utility,
ed. E. F. V. Scriven, Academic Press, Orlando, 1984, p. 104.
11 M. S. Platz, Acc. Chem. Res., 1995, 28, 487.
Compound 5
To a solution of [RuH2Cl2(PPri3)2] in thf (0.49 g, 1 mmol in 30
cm3) at room temperature was added dropwise a solution of
N3(mes) in the same solvent (0.32 g, 2 mmol in 10 cm3). The
colour of the reaction mixture changed successively from
yellow-orange to green-yellow to orange within 5 min. Stirring
was continued for ca. 3 h. At this time 31P NMR spectra of
aliquots showed complete consumption of the starting
material. After removal of volatiles under vacuum, washing of
the orange residue with light petroleum, extraction in toluene
(3 × 15 cm3), concentration of the toluene extracts to ca. 10 cm3
and cooling (Ϫ20 ЊC) gave orange crystals. Yield: 0.31 g, 45%.
12 G. A. Miller, S. W. Lee and W. C. Trogler, Organometallics, 1989, 8,
738.
13 P. T. Matsunaga, C. R. Hess and G. L. Hillhouse, J. Am. Chem. Soc.,
1994, 116, 3665.
14 P. Schwab, R. H. Grubbs and J. W. Ziller, J. Am. Chem. Soc., 1996,
118, 100.
15 Y. G. Godolobov and L. F. Kasukhin, Tetrahedron, 1992, 48, 1353.
16 G. Proulx and R. G. Bergman, J. Am. Chem. Soc., 1995, 117, 6382.
17 M. G. Fickes, W. H. Davis and C. C. Cummings, J. Am. Chem. Soc.,
1995, 117, 6384.
18 G. L. Hillhouse, G. V. Goeden and B. L. Haymore, Inorg. Chem.,
1982, 21, 2064.
19 V. V. Mainz and R.A. Andersen, Organometallics, 1984, 3, 675.
20 D. M. Hankin, A. A. Danopoulos, G. Wilkinson, T. K. N. Sweet
and M. B. Hursthouse, J. Chem. Soc., Dalton Trans., 1996, 4063 and
refs. therein.
21 A. A. Danopoulos, A. C. C. Wong, G. Wilkinson, B. Hussain-Bates
and M. B. Hursthouse, J. Chem. Soc., Dalton Trans., 1990, 315.
22 K. Baum, J. Org. Chem., 1968, 33, 4333.
23 R. O. Lindsay and C. F. H. Allen, Org. Synth., 1955, Coll. Vol. 3, 710.
24 T. A. Stephenson and G. Wilkinson, J. Inorg. Nucl. Chem., 1966, 28,
945.
25 H. Schmidbaur and G. Blaschke, Z. Naturforsch., Teil B, 1980, 35,
584.
26 C. Grunwald, O. Gevert, J. Wolf, P. Gonzalez-Herrero and H.
Werner, Organometallics, 1996, 15, 1960.
27 A. A. Danopoulos, G. Wilkinson, B. Hussain-Bates and M. B.
Hursthouse, J. Chem. Soc., Dalton Trans., 1991, 1855.
28 G. M. Sheldrick, SHELXS 86, Acta Crystallogr., Sect. A, 1990, 46,
467.
29 G. M. Sheldrick, SHELXL 93, Program for Crystal Structure
Refinement, University of Göttingen, 1993.
30 N. P. C. Walker and D. Stuart, Acta Crystallogr., Sect. A, 1983, 39,
158 (adapted for FAST geometry by A. Karaulov, University of
Wales Cardiff, 1991).
Compound 6
A mixture of trans-[RuCl2(PMe3)4] (0.48 g, 1 mmol) and
Li[NH(C6H3Pri2-2,6)] in di-n-butyl ether (20 cm3) was refluxed
for ca. 4 h. Removal of volatiles at 70 ЊC under vacuum, extrac-
tion of the yellow residue with light petroleum (30 cm3), filtra-
tion and concentration of the extracts to 5 cm3 and cooling
(Ϫ20 ЊC) for 2 d gave yellow very air-sensitive crystals. Yield:
0.2 g, 40%. NMR (C6D6): 1H, δ 7.40 (d, 1 H, aromatic), 7.02 (d,
1 H, aromatic), 6.52 (t, 1 H, aromatic), 3.4 (s br, 1 H, NH), 2.83
(spt, 1 H, CH3CHCH3), 1.75 and 1.72 (d, 2 H each, CH2CCH2)
1.32 (d, 6 H, CH3CHCH3), 1.15 (d, 18 H, PMe3) and 0.62 (d, 9
H, PMe3); 31P, δ 3.210 (t) and 0.30 (d), 2JP᎐P = 31 Hz.
Crystallography
X-Ray data for compounds 1–6 were collected at low temper-
ature; details are listed in Table 8. A FAST TV area detector
diffractometer with Mo-Kα radiation (λ = 0.71 069 Å) was
employed, as previously described.27 The structure of com-
pound 5 was solved using the PATT instruction of SHELXS
86,28 those of 1–4 and 6 via direct method procedures of the
same program. The structures were refined by full-matrix least
squares on Fo , using the program SHELXL 93.29 Corrections
2
for absorption were applied using the DIFABS program 30 with
maximum and minimum correction factors listed in Table 8. The
non-hydrogen atoms were refined with anisotropic thermal
parameters. All of the hydrogen atoms in compounds 1–5 were
included in idealised positions, except for the olefin protons of 1
which were experimentally located. All protons in 6 were located
Received 2nd May 1997; Paper 7/03028B
3184
J. Chem. Soc., Dalton Trans., 1997, Pages 3177–3184